Various types of electrical devices have increased performance and sound quality with a flat frequency response and a high signal-to-noise ratio (SNR). These types of electrical devices include micro-electro-mechanical systems (MEMS) devices, MEMS capacitive microphones, and electret condenser microphones (ECMs) technology, and so forth. A higher SNR is achieved with a more compliant structure but more compliant structures have lower resonance frequencies and poorer frequency response. Acoustic or mechanical damping can be added to reduce the height of the resonance peak but this damping leads to lower SNR. Additionally, reduction of a resonance peak can be achieved by inserting a notch filter into a signal processing system. However, the device resonance frequency is dependent on the processing system and/or the casing of the processing system. As such, the notch filter needs to be customized for each casing and/or system to properly dampen the frequency response and does not provide a standardized damping mechanism.
In particular, the notch filter attenuates the response at a specific frequency. This frequency is designed to be the resonance frequency so that the attenuation matches (in both frequency and magnitude) the resonance peak and cancels the resonance peak. However, when installed in a package, the case will shift the resonance frequency slightly but the notch frequency will remain unchanged. That is, the frequency of a notch filter is independent of the casing of a package but the location of the resonance frequency is not independent of the casing. Therefore, the notch location and resonance frequency location do not align and the appropriate damping response is not achieved.